ZWO ASI094MC Pro CMOS Camera User Review

To buy or not to buy, that’s the Question coming up to the mind along with every new interesting product that appears on the market…

Long story short

The answer is quite simple. For those, who are eager to hear my opinion, after spending 5 nights out with the camera I can give the answer. For me, definitively YES! I do not rate the products that I review on any scale, but if I would, I’d give 97% (that’s 97 points out of 100). Quite strange, based on the fact that I actually only bash things and criticize every single thing I see or get into my hands :-)

Short story long

Why did I purchase it?

when I already have (had) Moravian G3-11000 a full-frame (36x24mm) monochromatic „beast“ that performs so well? Because I wanted a newer technology (Sony IMX094 CMOS chip) and even could afford to have an OSC (color) chip if and only if the pixels are small so as I do not have to sacrifice the resolution (in sense of detail – image scale) and final pixel count – width and height after a 50% scale down. And I wanted a camera with really fast download time of single raw frames. And :-) since I mainly shoot LRGB/RGB (color) images of nebulae and dust (faint DSO objects) in real colors then a color camera might do just well. Last, but not least, it could also be a nice device for photography of Comets as they typically move very fast and it’s a hassle to switch the color filters (Red, Green, Blue) all over again with a monochromatic camera. And, I anyways wanted yet another 36x24mm camera for a second setup.

Unpacking the package, what’s in the box

TBD – work in progress.

Installing drivers, checking the camera

TBD – work in progress.

Before the first light

TBD – work in progress.

First light

TBD – work in progress.

Specification and technical data

TBD – work in progress.


Astrophotographs taken with the camera: Pavel Pech, ZWO ASI094MC Pro


it’s been a long time since I was so excited about a new gear!

- could have had the UV/IR cut filter installed by default (that’s where I take the 3% down from the final rating)
- the cooling delta -35 degrees Celsius may seem a bit low, but it’s not a big deal in fact
- you need to update your computer or get extra HDD space for the dark frame library as single raw FITs frame has 69 Megabytes!

+ everything else (it not only just works, it has everything I have ever asked for – apart from being mono :D )
+ 14bit, full-frame (36x24mm) camera with 13 stops in dynamic range
+ insane 36 megapixel resolution (7376 x 4928 pixels) even a 50% downsize results in a 9 megapixel image
+ it NEVER dewed up(!), the heating really works even in my humid environment (RH 93%)
+ it has a tilt adapter(!) but fortunately, my camera has the chip perfectly square to the front body
+ ultra low readout noise (for a color camera it’s irrelevant if the RN is 2e- or 4e-, anything <5e- is great)
+ insane FAST frame download time (about 1 second via full ASCOM protocol)
+ no issues with amp-glow anywhere
+ it's nice fit&finish, beautiful red circular body (no obstruction, no interference in Off-Axis-Guider)
+ contains USB2.0 hub to save one cable from PC to the guide camera as that can go via this hub
+ it's lightweight and compact size

And I have never got any corrupted frame downloaded from the camera.

Only a camera with latest full-frame BSI CMOS chip, Sony IMX251 having 42megapixels (remember it's a BSI and therefore the small pixels do not have the typical low sensitivity handicap) or some future big mono camera will outperform the ASI094MC Pro.



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QHY163M a 4/3″ mono CMOS camera – part #2

pech means bad-luck.

I am positive and open minded! Everything „bad“ is good for something else – let’s learn lessons and be stronger, better, smarter, experienced and full of hope that next time it will be OK :-) (either I am an „idiot“ :-) or maybe I just have insane patience – proved by the fact that I love to do astrophotography for about 8 years now which is quite a long time considering how much frustration this hobby brings).

But, unfortunately, after I got my repaired QHY163M back from China and captured (finally) some light frames I discovered a calibration issue – no need to mess with flats, just calibrating a single light with a single dark did not remove the amp-glow.

I have just recently sent the camera back to China again, for another repair.

Everybody can test his CMOS camera easily. Just take some 10 dark frames (at the same conditions). Create a master dark frame. Then, in the PixelMath, subtract the master from one selected (random pick) single dark frame. Max STF stretch it and see. You shall not see any amp-glow left, only a pure gaussian noise in the image (well, very, very subtle traces of amp-glow could be detected under certain, specific conditions, but really a fully working dark frame calibration must be able to remove it in an adequate way!).


dark frame only calibration issue
QHY163M a 4/3″ mono CMOS camera – part #1

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Bad Master Dark Frame Issue

never thought this can ever happen!

As I am paranoid about precise calibration (to get the best results afterwards), I’d never expect this to be the case with me. By a pure luck – using PixInsight’s STF and STF max function – to check that calibration of single frames (that I perform always in MaxIm DL Version 5.10) is correct I have (with help of a friend of mine who actually discovered the issue) found out, that at least for last couple of years I had an issue in the master darks and therefore in the calibration process.

What was done a wrong way? Simply see following two images.

wrong settings for a master dark

correct settings for a master dark

One would not believe that it makes a difference!

Checked with PixInsight’s PixelMath, when a single dark frame (instead of master dark frame) was used for both light frame calibration and flat field calibration, the issue observed was fixed. Strange! That meant I have constructed the master dark in a wrong way and this was not observable in MaxIm DL even after a huge (but linear) screen stretch. Thank’s to PixInsight’s STF I could have detected this minor (it’s very few ADUs) imperfection. From now on, I know that I must never save the individual master dark frame in MaxIm DL as IEEE float, but always construct it as median from Integer values. Positive outcome is that I can calibrate my last-year-taken data with a new set of master dark frames (hoping in better images then).


:-( :-)

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CCD Sony ICX694 vs. CMOS Panasonic MN34230

that is the Question.

Well, once I wanted to make a deep comparison article for my blog. But in the end, I was unable to gather reasonable data to do any meaningful comparison. It was also because of my-only issues with the CMOS camera. To post at least something :-) I’d like to say my conclusion – thanks to the even much lower readout noise of the Panasonic chip the CMOS beast is very, very capable and can perform as well as the superb ICX694 chip from Sony (high QE, low noise, low dark current, few hotpixels ever, no calibration needed). With the CMOS one needs to do a precise calibration and due to having only 12-bit ADC a stack of large amount of single frames is essential (as well as appropriate settings of the gain/offset values to get the best performance for given conditions). From the $$$ perspective, no surprise that it has become so popular.

Single 10 minutes, 3nm H-alpha image taken with ICX694 (using F/5 refractor of 100mm aperture):

Single 3 minutes, Red filter image taken with MN34230 (SW bin2x2, DSO preset using F/3.6 reflector of ~250mm aperture):

As I use the NGC7000 object for equipment tests, you may find more images taken with Kodak KAI-11002ME and Sony ICX694 on a F/4.3 refractor on the link below:
NGC7000, Pavel Pech

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Ultra Portable 6″ Astrograph for a 36x24mm Camera

Having the direct experience with carbon tube newtonians (zero focus shift during the night), precision of ASA focuser, quality of image (spots and almost real apochromaticity) produced by a superior coma correctors I have decided to have an own, small, ultra portable „refractor“ (best refractor is, for me, a custom built reflector) to be build. I have also considered to get the nice Vixen VSD 100 F/3.8, but for the price… knowing it won’t hold focus and won’t give small spots in the very corners of a large, smallish pixels camera, I managed to persuade myself to not go that route. The first thing I’d do with that would be a focuser upgrade anyway (for this scope I’d see a FLI’s Atlas as the right choice) which asks for almost 8K of money and still a lot of homework and custom built adapters.

The goal was to have zero vignetting – that could only be achieved by sacrifying the speed of the objective (F-stop) and the only option was a Paracorr VIP 3″ from TeleVue to get the focal plane out of the tube. I was assuming to get an effective F/5.6 objective (after including loss due to the large central obstruction from secondary mirror) that would have almost zero vignetting (goal met) and give reasonably great (good) star shapes in the very corners of a 36x24mm camera (goal not met).

Unfortunately, it turned out that the Paracorr is NOT suited for short focal length telescopes (below 900mm). I have had a call with Al from TeleVue on this matter for over a quarter of an hour and got a few days later e-mail response that there’s no remedy to this. Therefore my project for almost 4K of money failed.

Klaus Helmerichs Carbon Tube – 300 EUR
Orion UK 6″ Research Grade Primary mirror – 220 GBP
Orion UK 82mm Secondary – 72 GBP
ASA 3″ OK3 Focuser – 999 EUR
TeleVue VIP-3010 3″ Paracorr – 1290 EUR
Lacerta El-Panel + DewShield ~ 300 EUR
Manpower Costs and Other Material ~ 1000 EUR


Star Field Test Image


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QHY5III-178M quicktest

I have got this camera as a Christmas present in 2016 intended to be a replacement for previous QHY5II-L model used as a spare guide camera (therefore not really used at all). I have used it for the first time in my OAG, instead of my typical Moravian G1-301, to give it finally a try in June 2017. Result? It was really great, notably more sensitive than the 5II-L model which was far superior to any of the previous QHY5 or QHY5II models. Thanks to the BSI type of sensor (back side illuminated where the photodiodes do not occupy any space in front of pixels (are located on the other side) and thus making all photos fall to the pixel area, effectively using whole surface of the chip) and small pixels, variable gain, it would have been a great guide camera that is, moreover useful for some planetary and Moon work.

BTW as of today, I have just sold this one (after issue #2 with QHY163M) and plan to replace it with ZWO ASI290MM Mini :-) that I hope to use, one day, for a „basic and beginner’s“ shots of the Moon’s surface (as I still keep a Sloan z’ filter with 820nm+ bandpass).

ZWO ASI290MM-mini

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Expedition Korčula Island (Croatia) 2016

One of the best week(s) in my life!

Along with my fellow astrophotographer and a friend of mine Pavel Vabroušek we have had a wonderful week on the very late October/early November on the Korcula island. It was supported by 4 to 5 nights of imaging under a clear skies!

Some images:

Unfortunately, due to zero leisure time I was not yet able to process the data for the 3 to 4 images I took there. I have only improved one of my favorite Alnitak surroudings image with a Luminance data taken on Korcula island with a RGB color data taken on Tenerife.

Gallery of both Pavel’s images from the event:


Some time-lapse video:


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Expedition Orion Express 2014 (Tenerife)

One of the best week(s) in my life!

Was shooting 6 out of 7 nights there on the island, even on the last night (had to pack at 4am as my plane was leaving at 1pm). Big thanks to my fellow astrophotographer and a friend of mine Jan Čamek for his support!

See image gallery:




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QHY163M a 4/3″ mono CMOS camera – part #1

When the QHY’s competitor ZWO released first 4/3″ ASI 1600 mono camera, I was very tempted to get one immediately. I managed to sell my beloved Atik ONE with fabulous Sony IMX694 CCD chip (along with a full set of 3nm Astrodon narrow-band filters) for a decent price and got ready to dive into CMOS future (to get my feet wet). Bearing in mind the fact that since I became a proud father I have unbelievably little time to do any astrophotography I waited with the purchase.

In the end I decided to give QHY a try, because they have been doing DSO (cooled) cameras for very long time (assuming they would have enough experience to make quality products) and had resolved the optical window heating issue that I expected to be a problem for such a „large“ :-) 4/3″ chips.

My camera showed a defect in too much noise in the image. Also, when the TEC cooler was on there was more noise added than removed. Therefore I had to ship my camera back to China in February 2017 for repair.

End of story #1.



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Insight Astronomy Photographer of the Year 2016

My image was: shortlisted, in the group of prize winning images, not on the 3rd place in its category, but unfortunately also not the winning one. But 2nd place also counts! And I am happy for that!

Even though the winning image in the Stars and Nebulae category sparkled lot of public discussion on the image itself, as we, astrophotographers in vast majority do not count that type of composed image as an image itself (worth qualifying) it is, at least, an interesting idea. But from my side – it’s nothing „nice to look at“ and brings no wow effect at all. I’d be happier if the winner is a true, remarkable picture that everybody in our community would have to respect :-) On the other side, it’s very difficult for the jury to do their task, some of them are really no photographers at all and in the end – it is a miracle that a true DSO image (my attempt on this Perseus Molecular Cloud that I started in 2014 and finished in late 2015 in order to make it really a brilliant one) made it ever to the prize! As with everything, people are different, like different things (there’s no one size fits all) and I respect the results and am happy for being part of the competition. I have even made it there to Greenwich, London, to the ceremony award evening in person. Half of the prize money won was spent for the trip and second half for a new Orion UK 6″ primary mirror of Research Grade quality for my small and portable astrograph project :-)

NGC1333 widefield, vdB12, vdB13, vdB16, Barnard 202-206


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